[A single base substitution is responsible for the origin of "private" platelet Sra antigens affects molecular weight polymorphism of glycoproteins IIIa].
Some of the genetic polymorphisms of the platelet membrane glycoproteins (GP) IIIa are known to be responsible for alloantibody formation (Zw, Yuk). These antibodies may be involved in neonatal alloimmune thrombocytopenia, posttransfusion purpura, and sometimes in the state of refractoriness to platelet transfusion. Recently we described the first 'private' alloantigen on platelets residing on the 66-kDa membrane-bound fragment of GP IIIa. Further molecular genetic studies showed that the Sr polymorphism is associated with a C to T substitution at base 2004 in the GP IIIa gene resulting in an Arg/Cys amino acid dimorphism at position 636. Transfection of COS cells with recombinant forms of GP IIIa cDNA demonstrated that this amino acid dimorphism is responsible for the formation of the Sra epitope. Furthermore, the Sra variant of GP IIIa showed a slightly increased molecular weight which is presumably caused by different glycosylation.
Kroll
H
H
Institut für Klinische Immunologie und Transfusionsmedizin, Justus-Liebig-Universität Giessen, Deutschland.
Santoso
S
S
Kalb
R
R
Böhringer
M
M
Walka
M
M
Kiefel
V
V
Mueller-Eckhardt
C
C
D016824:Antigens, Human Platelet / Q000235:genetics*; D001803:Blood Transfusion; D006801:Humans; D007231:Infant, Newborn; D008970:Molecular Weight; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000235:genetics*; D017713:Platelet Transfusion; D017354:Point Mutation; D011110:Polymorphism, Genetic; D011693:Purpura / Q000235:genetics / Q000276:immunology; D013921:Thrombocytopenia / Q000235:genetics / Q000276:immunology
D016824:Antigens, Human Platelet; D019039:Platelet Glycoprotein GPIIb-IIIa Complex
Eine einzelne Basensubstitution ist verantwortlich für die Entstehung des "privaten" Thrombozytenalloantigens Sra und führt zum Molekulargewichtspolymorphismus des Glykoproteins IIIa.